There has so far been well known a color diffusion transfer photography using azo dye image-forming substance, in which a development under a basic condition results in providing an azo dye having different diffusibility from that of an image-forming compound itself. The compounds described in U.S. Pat. No. 3,928,312 are known in the art as a dye-releasing compound.
However, a dye-releasing efficiency of these dye-releasing compounds is not always high, and accordingly, there used to be involved the problem that a sufficient transferred density is not obtained.
Meanwhile, a conventional color diffusion transfer film unit is applied to indoor and outdoor photograph in many cases, and because of processing in a wide temperature range, the high processing temperature dependency of the transferred image density used is to be a problem.
These tendencies are particularly notable in the case where alkali processing is carried out at a low temperature. In such a sense, the techniques for improvements in transferred density and processing temperature dependency have been expected to appear.
With respect to means for improving in transferred density with an additive, a method in which a sulfonamide series compound in a form of a methanol solution is added to a dye-providing material-containing layer and processed at a high temperature in a dry film system is disclosed in JP-B-4-13701 (the term JP-B as used herein means an examined Japanese patent publication).
However, improvement effects for the transferred density and the processing temperature dependency were not observed with addition of the compounds disclosed in the patent described above.
Further, a method in which benzenesulfonamide is applied for the purposes of increasing the transferred density and improving the processing temperature dependency on a transferred temperature is disclosed in Japanese patent application No. 5-99458 (which corresponds to U.S. Ser. No. 08/233,701, now U.S. Pat. No. 5,418,111). While the improvement effect therewith is observed, further improvement has been desired.